1. Field of the Invention
This invention relates to a device for measuring the surface configuration of axially symmetric aspherics.
2. Description of the Prior Art
In the prior art devices for measuring axially symmetric aspherics such as aspheric lenses or the like, a member holding a sample lens has been swung through a predetermined angle of rotation about an axis orthogonal to the optic axis of the lens to thereby detect the angle of rotation and a carriage holding a stylus engaged with the sample lens has been provided for sliding movement along the optic axis and such carriage has been displaced by the point of contact of the sample lens with the stylus being displaced along the optic axis during the swinging movement of the sample lens, whereby the surface characteristic of the aspheric lens has been obtained from the amount of such displacement and the aforementioned angle of rotation. However, such prior art devices have required the surface of the sample lens to be always in contact with the stylus and if the bias force for establishing such contact was weak, an error of measurement might be caused and if the bias force was too strong, the stylus might damage the lens surface.